Display screen portion with a transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence for a display screen portion with a transitional graphical user interface

FIG. 2 is a second image thereof; and,

FIG. 3 is a third image thereof.

The appearance of the transitional graphical user interface transitions sequentially between the images shown in the figures. This process or period in which one image transitions to another forms no part of the claimed design.

The broken lines showing of a portion of a display screen and portions of the graphical user interface illustrate portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a display screen portion with a transitional graphical user interface, as shown and described. 